Saturn Section        


November 19, 2016

A Special Cassini Mission Pro-Am Note to ALPO Saturn Observers

Saturn observers worldwide are alerted, as of this writing, that NASA’s unprecedented close-range surveillance of the planet by the Cassini spacecraft for nearly thirteen years, which started back on April 1, 2004, will enter the final year of its epic voyage during the 2016-17 apparition. The spacecraft is expected to conclude its remarkable odyssey on September 15, 2017 when it plunges into the Saturn’s atmosphere, but between now and then, Cassini will complete a remarkable two-part endeavor. The first phase involves weekly orbital passages of the spacecraft within 7,800 km of the center of Saturn’s narrow braided F-ring starting November 2016. Mission scientists hope to capture high-resolution images of small satellites and study other structures within the ring for the first time since an initial close fly-by back in 2004.

The second phase is being dubbed the “Grand Finale” that involves a gravity assist by a close flyby of Titan to reconfigure of the orbital path of Cassini allowing it to make over twenty passages through the gap that is only 2,400 km wide between Saturn and the inner edge of the ring system starting April 27, 2017. The objective of this phase is to analyze fine dust particles in the rings and sample outer regions of the atmosphere of Saturn, while also imaging the planet’s atmosphere closer than in the past, mapping the planetary magnetic and gravitational field, gaining greater knowledge of Saturn’s internal structure and rotational dynamics, and acquiring a keener understanding perhaps of the mass of the ring system.

ALPO Saturn observers who have been participating already in our on-going Pro-Am activities, as well as anyone else who wants to join us in our continuing efforts, are highly encouraged to continue to submit systematic observations and digital images of the planet at various wavelengths throughout the 2016-17 apparition. The spacecraft will very likely return some spectacular images of Saturn’s northern hemisphere and any discrete phenomena before the two aforementioned plunges into the rings and ultimately into the atmosphere of Saturn in mid-September 2017.


December 12, 2010


On December 10, 2010 between 18:01 and 18:13UT Anthony Wesley of Murrumbateman, Australia submitted
several images at visual and IR wavelengths of a prominent white spot situated in the North Tropical
Zone (NTrZ) using a 36.8cm (14.5in) Newtonian.

Likewise, Marc Delcroix of Tournefeuille, France submitted several images at various wavelengths of
the NTrZ white spot using a 25.4cm (10.0in) SCT.

Data derived from these images suggest the NTrZ was located roughly at longitude 255° and Saturnicentric
latitude around 33/33.5°.

The NTrZ storm may be bright enough to be detected visually with sufficient aperture and good seeing.

Observers are requested to begin submitting their observations and images to the ALPO Saturn Section
as soon as possible.

Saturn North Hemisphere

White Spot Alert


This album has 4 photos and will be available on SkyDrive until 3/12/2011



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